As a result of combining saccharin and cyclamate, the German researchers believe they have solved a 60-year old challenge that restricts sweetener use in high concentrations.
“Numerous sweeteners exhibit undesirable off-tastes," said lead author Dr Maik Behrens from the German Institute of Human Nutrition Potsdam-Rehbruecke.
“To overcome this problem, the food industry is constantly searching for novel sugar substitutes and frequently resorts to using blends combining non-caloric sweeteners in a single formulation."
In addition to stimulating sweet taste receptors, sugar substitutes also activate bitter taste receptors, known as TAS2Rs, resulting in the familiar unpleasant taste.
Manufacturers have turned to stevia-derived sweeteners – artificial sweeteners blended with stevia – in the hope that it could lead to better flavours.
Erythritol has proven a suitable blending partner, having found a chemical bond with stevia along with other sweeteners including inulin, isomalt, and glycerin in order to counter erythritol’s ‘strong cooling effect’.
A well-established and accepted sweetener blend is acesulfame-K with aspartame, widely used in products ranging from soft drinks to chewing gum.
The sweeteners work in a synergy that allows low concentrations of acesulfame-K, which can be bitter at higher concentrations, to blend seamlessly with aspartame, which does not have the bitter components.
Dr Behrens and fellow author Wolfgang Meyerhof from the Institute began by using a cell-based system that consists of various taste receptors in human cells.
The team then tested receptor responses to different concentrations of saccharin and cyclamate.
They discovered that cyclamate strongly inhibited the saccharin-induced activation of two bitter taste receptors called TAS2R31 and TAS2R43.
This effect occurred at concentrations where cyclamate itself does not provoke a side taste.
Similarly, saccharin blocked the cyclamate-induced responses of a bitter taste receptor called TAS2R1.
“Saccharin and cyclamate belong to the oldest-known high-potency synthetic sweeteners,” Dr Behren said.
“We were able to discover with our cell assay completely novel features of these molecules, namely their bitter-blocking ability."
Mechanism of action
In putting forward a potential mechanism of action, the team pointed to the mutual suppression of TAS2R in accounts for the non-caloric sweetener blend taste.
In addition, the results indicate that mixtures of two or more bitter compounds could exhibit lower overall bitterness as the result of inhibition between the substances.
In contrast, the sweet taste receptor did not show activation by saccharin-cyclamate blends, suggesting that maximal sweetness levels are dominated by the most effective sweetener.
"Once the activation and inhibition profiles of the 25 human bitter taste receptors have been investigated in great detail, it will be possible to tailor the composition of mixtures to develop novel sweetener formulations," Dr Meyerhof added.
Source: Cell Chemical Biology
Published online ahead of print: doi.org/10.1016/j.chembiol.2017.08.004
“Blends of Non-caloric Sweeteners Saccharin and Cyclamate Show Reduced Off-Taste due to TAS2R Bitter Receptor Inhibition.”
Authors: Maik Behrens, Kristina Blank, Wolfgang Meyerhof